Let's pretend the IETF in its wisdom decides that The New SPF
absolutely may not reuse TXT.
I'm against a new RR type instead of TXT for SPF, unless IETF absolutely
requires it. RFC 3597 is still too immature. If it had come out a year or two
earlier, then I'd probably support it now.
The good argument against using a new RRtype, of course, is that you
don't want to require the whole world to upgrade their DNS servers
just to be able to publish SPF records. This is the argument that
reflects the last 6 months of consensus on the SPF list.
Another couple good arguments against it:
In addition to the servers not supporting it, many querying libraries also do
not support RR types. This makes implementation of SPF much more difficult for
some platforms.
Well over 14,000 domains already support SPF using TXT. Do we support backward
compatibility for existing SPF records and for domains whose servers who do not
support RR types? If so, then why bother having two records that mean the same
thing?
Basically we are entertaining the use of an RR type record for purely aesthetic
reasons. Which looks better, a TXT "v=spf1" record or a TYPE#### record? The
TYPE#### record doesn't function better, isn't easier to understand, and
certainly doesn't improve interoperability.
Just my two cents,
Michael R. Brumm